1. Field of the Invention
This invention relates to a liquid crystal display, and more particularly to a liquid crystal display capable of preventing the generation of metal impurities.
2. Discussion of the Related Art
Liquid crystal displays are smaller in size than cathode ray tubes and are used extensively in potable televisions and monitors of lap-top computers. Active matrix liquid crystal displays use thin film transistors (TFTs) as switching devices to display pictures corresponding to video signals (e.g., television signal) inputted to a pixel matrix.
The pixel matrix contains pixels arranged at crossings between the gate lines and data lines. Each pixel within the pixel matrix includes a liquid crystal cell that controls light transmittance of a liquid crystal in accordance with a voltage level of a data signal applied from the data line. Installed where the gate and data lines cross each other, TFTs switch the data signal in response to the scanning signal (gate pulse) applied from the gate line to transmit data signals to liquid crystal cells.
Referring to FIGS. 1 and 2, liquid crystal displays typically include a bottom cover 10, a top case 34, a liquid crystal display module disposed between the bottom cover 10 and the top case 34, and a driving circuit 40 for driving the liquid crystal display module.
The liquid crystal display module includes a liquid crystal display panel 30 for displaying pictures and a backlight unit for generating light. Though not shown, the liquid crystal display panel 30 includes an active area, where pictures are displayed, and a non-active area surrounding the active area, where no pictures are displayed.
The liquid crystal display panel 30 includes an upper substrate 30a supporting a color filter array and an alignment film (not shown), a lower substrate 30b supporting a TFT array and an alignment film (not shown), and liquid crystal material (not shown) interposed between the upper substrate 30a and the lower substrate 30b. 
The backlight unit includes a lamp assembly comprised of at least one lamp 20a for generating light, a light guide panel 20d for converting the generated light into a planar light source, a lamp housing 20b provided so as to cover the lamp 20a and to reflect the generated light toward a light guide panel 20d, a reflection plate 20c for reflecting the generated light toward the liquid crystal display panel 30, and at least one optical sheet 20e for diffusing the converted light transmitted by the light guide panel 20d. 
A main support 32, arranged on the backlight unit, supports the liquid crystal display panel 30.
A driving circuit 40 for driving the liquid crystal display panel 30 includes a printed circuit board (PCB) 40c, a tape carrier package (TCP) 40a for connecting the liquid crystal display panel 30 with the PCB 40c, and driving integrated circuits (D-ICs) 40b mounted on the TCP 40a via a tape automated bonding (TAB) technique.
The D-ICs 40b supply data signals and scanning signals to the data lines and the gate lines of the liquid crystal display panel 30, respectively, in response to control signals outputted from the PCB 40c. The lower substrate 30b is bonded to the TCP 40a upon the application of high temperature and high pressure, while the TCP 40a is connected to the PCB 40c via a flat TAB technique. In applying the flat TAB technique, the non-active area provided is relatively large, which reduces the active area. In order to increase the relative size of the active area, TCP 40a may alternatively be connected to the PCB 40c by a TAB technique wherein the PCB 40c is arranged at the side of the top case 34.
The top case 34 covers the edge and side surfaces of the liquid crystal display panel 30 and several other optical components (not shown). Accordingly, the top case 34 protects the liquid crystal display panel 30 from external impacts.
The bottom cover 10 is formed of a metal material (e.g., aluminum Al). Screws 50 are provided within screw holes arranged at one side of the bottom cover 10 near the PCB 40c in order to secure the liquid crystal display panel within the liquid crystal display. As the screws 50 pass through each of the screw holes, the PCB 40c and the bottom cover 10 become secured together. When the screws 50 are received into the screw holes, however, metal impurities from the PCB 40c and the bottom cover 10 are generated. The metal impurities contact electrodes arranged at portions of the TCP 40a located near the screw holes and act to short circuit the electrodes. Securing the bottom cover 10 to the PCB 40c via the aforementioned screw hole/screw system is difficult and requires equipment capable of preventing the generation of metal impurities to the TCP 40a. 